• Advances in Energy Research
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• v.3 no.3
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• pp.143-155
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• 2015

The Nile blue has been used as a photosensitizer with Arabinose as a reductant in photogalvanic cell for optimum conversion efficiency and storage capacity. Reduction cost of the photogalvanic cell for commercial utility. The generated photopotential and photocurrent are 816.0 mV and $330.0{\mu}A$ respectively. The maximum power of the cell is $269.30{\mu}W$ where as the observed power at power point is $91.28{\mu}W$. The observed conversion efficiency is 0.6095% and the fill factor 0.2566 has been experimentally found out at the power point of the photogalvanic cell, whereas the absolute value is 1.00. The photogalvanic cell so developed can work for 120.0 minutes in dark if it is irradiated for 200.0 minutes that is the storage capacity of photogalvanic cell is 60.00%. The effects of different parameters on the electrical output of the photogalvanic cell have been observed. A mechanism has also been proposed for the photogeneration of electrical energy.

• Ceramist
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• v.21 no.3
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• pp.233-248
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• 2018

Photosynthesis of plant, algae, and certain types of bacteria can convert solar energy to electrons at high efficiency. There have been many research investigations to utilize this mechanism to develop photosynthetic bio-solar energy systems. In this article, the fundamentals of photosynthetic energy conversion mechanism are explained and various approaches are introduced and discussed.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.406-409
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• 1998

Sound absorbing materials are divided into several types according to the appearances and the characteristics. Basic mechanism of sound absorption in various sound absorbing materials is the conversion of sound energy into hat energy. Here the important elements which govern by the conversion from sound into heat depend on the type of materials. (omitted)

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.16.2-16.2
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• 2009

Developing a low cost printing material that can replace silver for the formation of a conducting pattern is an important issue in printed electronics. We report a novel approach using a non-oxidized copper material during the printing and sintering process under ambient conditions, which was previously considered unachievable. An attempt was made to understand the conversion process of cuprous oxide nanoparticle aggregates on metallic copper crystals through chemical reduction in the solution phase. The detailed mechanism for this conversion, including the role of the surfactant and crystal growth, was examined.

• Korean Journal of Materials Research
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• v.16 no.5
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• pp.323-328
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• 2006

In situ electrical conductivity measurements on $V_2O_5WO_3/TiO_2$ catalysts were carried out at between 100 and $300^{\circ}C$ under pure oxygen, NO and $NH_3$ to investigate the reaction mechanism for ammonia SCR (selective catalytic reduction) de NOX. The electrical conductivity of catalysts changed irregularly with supply of NO. It was, however, found that the electrical conductivity change with ammonia supply was regular and the increase of electrical conductivity was mainly caused by reduction of the labile surface oxygen. The electrical conductivity change of catalysts showed close relationship with the conversion rate of NOx. Variation of conversion rate in atmosphere without gaseous oxygen also showed that labile lattice oxygen is indispensable in the initial stage of the de NOx reaction. These results suggest that liable lattice oxygen acts decisive role in the de NOx mechanism. They also support that de NOx reaction occurs through the Eley?Rideal type mechanism. The amount of labile oxygen can be estimated from the measurement of electrical conductivity change for catalysts with ammonia supply. This suggests that measurement of the change can be used as a measure of the de NOx performance.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.29-35
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• 2003

We studied the water splitting into $H_2$ and $O_2$ using two different semiconductor photo catalysts and redox mediator, mimicking the Z-scheme mechanism of the photosynthesis, $H_2$ evolution took place on a Pt-$SrTiO_2$ (Cr-Ta doped) photocatalyst using $I^-$ electron donor under the visible light irradiation. The Pt-$WO_3$ photocatalyst showed an excellent activity of the $O_2$ evolution using $IO_3^-$ electron acceptor under visible light. $H_2$ and $O_2$ gases evolved in the stoichiometric ratio($H_2/O_2$=2) under visible light using a mixture of the Pt-$WO_3$ and Pt-$SrTiO_3$ (Cr-Ta doped) suspended in NaI aqueous solution. We proposed a two-step photo-excitation mechanism using redox mediator under the visible irradiation.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E2
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• pp.107-120
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• 2002

Dimethyl sulfide (DMS) is the major sulfur gas released from the ocean. The atmospheric DMS released from the ocean is oxidized mainly by hydroxyl (OH) radical during the day and nitrate (NO$_3$) radical at night to form sulfur dioxide (SO$_2$) as well as other stable products. The oxidation mechanism of DMS via OH has been known to proceed by two channels; abstraction and addition channels. The major intermediate product of the addition channel has been known to be dimethylsulfoxide (DMSO) based on laboratory chamber studies and field experiments. However, a branching ratio for DMSO formation is still uncertain. The reaction of DMSO with OH ultimately produces SO$_2$and dimethylsulfone. The major product of the abstraction channel has known to be SO$_2$from laboratory chamber studies. But overall conversion efficiency for DMS to SO$_2$from DMS oxidation is still inconsistent in the literature. Based on laboratory and field studies, the conversion efficiency from the abstraction channel is likely to be greater than 0.5, while that from the addition channel is likely to be greater than 0.6. Overall conversion efficiency from DMS to SO$_2$might be greater than 0.5 based on the above two values in the remote marine boundary layer (MBL). This high efficiency in the remote MBL is supported by strong coupling between DMS and SO$_2$measurements with high temporal resolution.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.1-8
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• 1999

Most carbohydrates exist in nature in an insoluble state, which reduces their susceptibility towards various carbohydrases. Accordingly, they require intensive pretreatment for structural modification to enhance an enzyme reaction. The direct conversion of insoluble carbohydrates has distinct advantages for special types of reaction, especially exo-type carbohydrase; however, its application is limited due to structural constraints. This paper introduces two novel heterogeneous enzyme reaction systems for direct conversion of insoluble carbohydrates; one is an attrition coupled enzyme reaction system containing attrition-milling media for enhancing the enzyme reaction, and the other is a heterogeneous enzyme reaction system using extruded starch as an insoluble substrate. The direct conversion of typically insoluble carbohydrates, including cellulose, starch, and chitin with their corresponding carbohydrases, including cellulase, amylase, chitinase, and cyclodextrin glucanotransferase, was carried out using two proposed enzyme reaction systems. The conceptual features of the systems, their reaction characteristics and mechanism, and the industrial applications of the various carbohydrates are analyzed in this review.

• Natural Product Sciences
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• v.27 no.3
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• pp.208-215
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• 2021

𝛽-Patchoulene (𝛽-PAE) is a tricyclic sesquiterpene which performed many potential bioactivities and can be found in patchouli oil but in very low concentration. This study aimed to obtained 𝛽-PAE in high concentration by conversion of patchouli alcohol (PA) in patchouli oil under acid catalyzed reaction. Patchouli oil was fractinated by vacuum distillation at 96 kPa to get the fraction with the highest PA content. H₂SO₄ and ZnCl₂ were used respectively as homogeneous and heterogeneous acid catalysts in the conversion reaction of the selected fraction. Patchouli oil, the fractions and the products were analysed by using GC-MS and FTIR instruments. Moreover, the interaction of 𝛽-PAE to COX-2 protein was studied to understand the antiinflammation activity of 𝛽-PAE. The results showed that patchouli oil contains 25.3% of PA. The selected fraction which has the highest PA content (70.3%) was distilled at 151 - 152 ℃. The application of ZnCl₂ catalyst in conversion reaction did not succeed. In contrast, H₂SO₄ as a catalyst in acetic acid solvent succeeded in converting the overall fraction of PA to 𝛽-PAE. Furthermore, the molecular docking study of 𝛽-PAE against COX-2 enzyme showed van der Waals and alkyl-alkyl stacking interactions on ten amino acid residues.

• Information Systems Review
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• v.10 no.2
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• pp.123-135
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• 2008

The online advertising industry's business model undertakes the change from CPM (cost-per-mille)-based to CPC(cost-per-click)-based. However, due to the problem of 'Click Fraud', CPA (cost-per-action) has been regarded as a new step. For CPA, publishers need to get information after a user clicks an advertisement. Therefore, in CPA, the key is to get Conversion Action Data (CAD). This paper introduces two existing mechanisms for getting CAD, compare their characteristics, and analyze their limitations. Then the two new mechanisms are introduced and their requirements and feasibility are analyzed. Lastly, we compare the existing two and the new two mechanisms, and point out each mechanism's business possibility, value and Application Area. This paper will help publishers choose the most appropriate mechanism on the basis of their situation.